A quadruple-double is a basketball term in which a player reaches double figures in four statitical categories. This includes points, assists, rebounds, steals, blocks, and even turnovers. This is probably the hardest feat to accomplish in basketball. In the NBA, it has only been accomplished a mere five times.
On November 17, 2000, Jason Kidd, back when he played on the Phoenix Suns, scored 18 points, 10 assists, 12 rebounds and 14 turnovers against the New York Knicks. Some don't consider turnovers a relative category to award him a quadruple-double status, but nevertheless he did it.
On February 17, 1994 (6 seasons before another one was to occur), David "The Admirial" Robinson of the San Antonio Spurs, scored 34 points, 10 rebounds, 10 assists, and 10 blocks against the Detroit Pistons. Besides Robinson and Kidd, the only other players in the NBA to do this are Hakeem Olajuwon, Alvin Robertson and Nate Thurmond. According to user Orange Julius, both Olajuwon and Thurmond achieved he quadruple-double via points/rebounds/assists/blocks. Alvin Robertson did it via points/rebounds/assist/steals. Thanks!!
Similar, but easier tasks include the double-double, and the triple-double.